Battery Pack Insulation Resistance Circuit With Voltage Recalculation
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Solution Overview
Problem
Existing insulation resistance measurement circuits in battery management systems are bulky and expensive due to the need for high-end components to handle increasing battery pack voltages, necessitating a reduction in size and cost while maintaining performance.
Innovation Solution
A measurement circuit is connected between one terminal of a battery pack and a chassis, using a voltage measurement unit and insulation resistance calculation unit to calculate insulation resistance, with recalculations based on voltage changes over time when resistance falls below a threshold.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If measurement resistors and switching elements are connected between high voltage battery poles and chassis to measure insulation resistance, then measurement accuracy is maintained, but device size and cost increase due to bulky high-end components
Solution Approach 1:
The patent extracts the measurement circuit from the traditional configuration that requires connection to both battery poles and chassis, simplifying it to connect only to one battery pole. This removes the need for bulky measurement resistors and switching elements connected to the chassis, thereby reducing device size and cost while maintaining measurement capability through alternative calculation methods
Solution Approach 2:
The patent replaces the traditional electrical measurement system (using physical measurement resistors and switches) with a calculation-based system. Instead of directly measuring resistance through physical components connected to chassis, the system calculates insulation resistance based on voltage measurements and charge/discharge characteristics, eliminating the need for bulky high-end components
2Reliability
If high-end components are used to handle increasing battery pack voltages, then measurement reliability is maintained, but device cost increases
Solution Approach 1:
The patent changes the measurement parameters from direct resistance measurement using high-voltage-rated components to voltage-based indirect measurement. By measuring voltage at lower potential points and calculating resistance through charge/discharge characteristics, the system maintains reliability under high voltage conditions without requiring expensive high-voltage-rated measurement components
3Device complexity
If measurement circuit is simplified to reduce size and cost, then device complexity decreases, but measurement precision may deteriorate
Solution Approach 1:
The patent implements feedback mechanisms by performing multiple voltage measurements at different time points during charge and discharge cycles. The system uses the charge amount and discharge amount as feedback parameters to calculate and verify insulation resistance, ensuring measurement precision is maintained even with the simplified circuit configuration
Solution Approach 2:
The patent performs preliminary charge and discharge actions before the actual insulation resistance measurement. By pre-charging and pre-discharging the battery at controlled rates and measuring the resulting voltage changes, the system prepares the electrical state necessary for accurate insulation resistance calculation, compensating for the simplified measurement circuit
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach reduces the size and cost of the battery management system while maintaining performance equivalent to traditional circuits, with improved accuracy through recalculations for low resistance values.
Implementation Method 1
a voltage measurement unit that measures a voltage from the measurement circuit, and an insulation resistance calculation unit that calculates insulation resistance of the battery pack based on the voltage measured by the voltage measurement unit
Data Source
AI summary
An apparatus for calculating battery resistance according to an embodiment of the present invention can include a measurement circuit connected between one terminal among a positive (+) terminal and a negative (−) terminal of a battery pack and a chassis, a voltage measurement unit that measures a voltage from the measurement circuit, and an insulation resistance calculation unit that calculates insulation resistance of the battery pack based on the voltage measured by the voltage measurement unit. When the calculated insulation resistance is less than a preset threshold, the insulation resistance calculation unit can recalculate the insulation resistance based on an amount of change in voltage of the battery pack over time.